A biopsy device for use in excising tissue from a human body includes an outer member and an inner member and a rotary drive means for rotating the inner member with respect to the outer member. The outer member includes a cylindrical outer body portion, an outer cutout portion defined in the outer body portion and an acute outer knife edge portion formed to extend along an edge of the outer cutout portion and a cutting tip provided at a tip end of the outer body portion. The inner member includes an inner body portion inserted into the outer member and an inner cutout portion defined in the inner body portion to obliquely extend with respect to a longitudinal direction of the inner body portion and an acute inner knife edge portion formed to extend along an edge of the inner cutout portion.
